All discussions around Posts, Connections, Mentions or Reports are shared with all members regardless of their role. But while initiating the discussion, you can choose to restrict viewership by clicking on the drop-down on the discussion tab. From there, you can choose* individual members or roles to involve only specific people in a discussion.
You can choose the Marketing team for instance, to discuss a campaign idea and get specific feedback on it. You can do so by clicking on the drop-down menu and choosing Custom Share. Here, you can add any specific team/teams that you want.
You can pre-assign these teams just as easily. Just go to Settings icon on the top right of your screen and choose 'Roles and permissions' from the long tab that appears. Here you can create specific roles like 'Marketing' or 'Intern' under which you can add members. And yes, you have the flexibility to change these settings even after a discussion has gone live.
In case you've signed up for the Agency Plan for managing social media for multiple clients, you have the added option of sharing a discussion with both your clients and team members/roles simultaneously from the same drop-down visibility menu.
All discussions - irrespective of the plan- can be accessed by the Admin of the portal.